O/B shaft length affect performance

Waltswagon

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Will a long shaft 35hp Evinrude affect performance on my 13' Boston Whaler which has a short shaft on it now?
 

zopperman

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Re: O/B shaft length affect performance

depends on the height of the transom. the anti vent plate should be about level with the keel

Welcome aboard :D
 

smokeonthewater

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Re: O/B shaft length affect performance

yep.... won't be worth a chit.... you could look into a jack plate to raise the engine to the proper height
 

zopperman

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Re: O/B shaft length affect performance

or his current set up could be wrong too... Wanna post up a pic of it before we jump to jackplates?
 

ezmobee

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Re: O/B shaft length affect performance

or his current set up could be wrong too... Wanna post up a pic of it before we jump to jackplates?

I don't think any "jumping" has been done. OP clearly stated he's got a long shaft motor and short shaft transom. Pretty cut and dry.
 

smokeonthewater

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Re: O/B shaft length affect performance

yeah a 13' whaler would be a shortshaft transom

EDIT: well looks like it could be 15 or 20..... I took his question to indicate that he had a 15" transom...

In case that was wrong then I'll put it this way... The engine needs to match the transom or you need to adapt it either by use of a jack plate, modification of the transom, or modification of the engine
 

zopperman

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Re: O/B shaft length affect performance

I don't think any "jumping" has been done. OP clearly stated he's got a long shaft motor and short shaft transom. Pretty cut and dry.

He said he currently has a short shaft motor.. not necessarily a short shaft transom, but I would agree with smoke that it probably is seeing as its a smaller boat:

History

From continuous wave 13' whaler history:

In 1972, the transom height was raised to 20 inches from 15 inches, probably to keep pace with the use of higher horsepower motors. Both the hull and liner laminates changed to the Desert Tan gelcoat color. The hull had been white and the cockpit either a baby blue or turquoise.
 

Home Cookin'

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Re: O/B shaft length affect performance

I have also seen 13' whalers where the short transom was raised. But generally the 13' is a short shaft transom.
How long after 1972 did they keep makling the taller transom? I recall they are now short shafted. Maybe it was an option?
 

zopperman

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Re: O/B shaft length affect performance

I have also seen 13' whalers where the short transom was raised. But generally the 13' is a short shaft transom.
How long after 1972 did they keep makling the taller transom? I recall they are now short shafted. Maybe it was an option?

1972 changed to 20-inch height transom,
hull and interior gelcoat changed to
desert tan.
 

JB

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Re: O/B shaft length affect performance

I have also seen 13' whalers where the short transom was raised. But generally the 13' is a short shaft transom.
How long after 1972 did they keep makling the taller transom? I recall they are now short shafted. Maybe it was an option?

Not so. The original 13' hull was 15" until 1972; 20" thereafter. It never changed back and was built that way until at least 2000. 10 years vs. 30 years makes it generally a 20" transom. I really doubt that current 13' models are 15" transoms.

OP needs to specify what model and year his Whaler is. Too easy to assume he has a 15" transom.
 

Home Cookin'

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Re: O/B shaft length affect performance

yep--according to the BW website, the 13's, and even the 11's are 20" transoms. Learn something new every day. Of course, we all know the real whalers are the blue-hulls.
 
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